Remove automated GitHub Actions and simplify CI/CD

- Remove greetings, monitoring, release-drafter workflows
- Remove dependabot, stale bot configurations
- Update remaining workflows to only run on main branch pushes
- Simplify CI/CD to just run tests and linters on main branch

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jeremymanning

.github/.stale.yml

@@ -1,6 +1,9 @@
 name: build
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
 
 jobs:
   build: